Provides for a laboratory which is capable of: maintaining a colony of up to 3,000 mice; providing the technical staff and equipment capable of irradiating mice, preparing sterile cell suspensions, injecting mice intraperitoneally or intravenously with cells or virus, culturing mouse cell lines, bleeding mice, palpation of mice for detection of tumors;and transporting mice and tissues twice daily between the contract facility and the Clinical Center, NIH.